Project Summary/Abstract The proposed work investigates possible consequences of sensorineural hearing loss and age in the weighting of complex auditory information, which is in line with NIDCD's mission and strategic plan of providing new insights into the consequences of disordered hearing. Most of the sounds in our environment are complex in that they contain information across many frequencies simultaneously (e.g., speech). In a given perceptual task, listeners may weight certain frequencies more than others for efficiency. Typically, listeners with hearing loss display greater high-frequency hearing loss than low-frequency hearing loss, which some studies suggest may impact how listeners weight frequency information. However, these studies are inconsistent regarding whether HI listeners weight information in regions of greater hearing loss more or less than other regions. The experiments in Aim 1 are designed to understand the sources of these discrepant findings by testing the same hearing-impaired (HI) and normal-hearing (NH, as a referent population) listeners (both younger and older adults) in a sampling of cross-frequency weighting tasks. Another important consideration is that most sounds are not only spectrally complex, but also change over time. Some previous studies have suggested that spectral weights might be quite flexible, but none have charted the time course of this presumed adaptability. The experiments in Aim 2 examine the adaptability of spectral weights over time for NH and HI younger adults and older adults. The tasks require the listener to place maximal weight at a particular frequency. The target frequency is then changed across trials to determine how rapidly listeners make a corresponding change in weights. Previous studies have found large intersubject differences in observed weighting patterns for both NH and HI listeners. The analyses and measures in Aim 3, examining factors related to hearing loss and cognitive abilities, are intended to understand sources of these individual differences. The PI of this career development application is an Au.D./Ph.D. Research Assistant Professor at Boston University where this work will be conducted. The PI's short-term goals are to receive training in the research areas proposed in this application and other areas beneficial to her future career. These are directly related to the PI's long-term career goal which is to continue this work independently as an R01-funded, tenure-track faculty member at a university. The PI does not have prior experience with these weighting methods, analyses, or with research examining the effects of age. Therefore, the research career development plan involves training with a mentor and collaborator team consisting of experts in the relevant analyses and in auditory research with older populations to gain expertise in this areas. Other training objectives include gaining expertise in data interpretation, signal processing, and objective measures of auditory function. Training activities include presentations at auditory and aging conferences; coursework in statistical analyses and signal processing; and workshops and mentor- guided training for faculty career and R01 writing preparation.